Diversity of aquatic insects of Dibru River near Dibru Saikhowa National Park, Assam, North East India

A study was conducted on aquatic insect community of Dibru River at three sites, Guiijan ghat (DS1), Kaliapani ghat (DS2) and Khantigwali ghat (DS3) of Dibrugarh district near Dibru Saikhowa National Park. The sampling of aquatic insects and water was done in replicates during September 2014-2015. The study recorded 4 orders, 8 families, 12 genera and 12 species of aquatic insects. Highest density of order Hemiptera was recorded in pre monsoon and lowest and same density was recorded of order Odonata and Coleoptera in monsoon and winter. Seasonal variations of environmental variables of water were found moderate. Density of aquatic insects showed significant negative relationship with phosphate. The study revealed low Shannon Weiner Diversity Index values of aquatic insects (Shanon Hless than1) in all the sites indicating perturbed conditions of water. Canonical Correspondence Analysis (CCA) showed that the species environmental correlations of axis 1 and axis 2 were high.